Neural Networks for Real-Time Sensory Data Processing and Sensorimotor Control.
CASE WESTERN RESERVE UNIV CLEVELAND OH
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Our experimental work has focused upon two areas. First, we have completed our analysis of the turning movements. We have also videotaped several free-ranging animals to compare to our more precise tethered preparations. From both of these sets of data it is now clear that there are actually three types of turns. In all three variations, the actual turning motion is generated by the middle legs and depends precisely on the joint between the femur and tibia of that pair of legs. In all cases the femur-tibia joint of the middle leg extends on the side ipsilateral to the wind and flexes on the side contralateral to the wind. Thus both legs move towards the wind and in a freely moving animal this would turn it away from the wind source. The three types of turns are distinguished by anterior-posterior leg movements which are generated by the coxal-femur joint. In type I turns, both the hind legs thrust back providing power for the turning movement. In type II turns, the contralateral legs move forward pulling the animal back on the contralateral side while pushing forward on the ipsilateral side. The result is a much more rapid turn similar to that made by a rowboat in which the oarsman pushes on one oar while pulling on the other. These turns are associated with wind from 90 degrees and from the front. In the type III turn, both hind legs move forward but the feet are in contact with the ground so that the animal actually backs away from the wind source while the middle legs generate a turning movement.
- Anatomy and Physiology